A weather model is a mathematical description of the physics of the atmosphere. As such, weather models incorporate assumptions that the sun adds energy, gases rise from the surface and convection can lead to winds, among other basic assumptions. Numerical weather prediction is done by solving equations relating to these assumptions (and often, other inputs) on a 4-dimensional grid (e.g., latitude, longitude, altitude, time), and is complementary to actually observed weather patterns or behavior. A solution yields predictions of the following variables, among others, both at surface and upper air locations: temperature, humidity, moisture, pressure; wind speed and direction; cloud cover and visibility; and precipitation type and intensity.
However, configuring a weather model for a new target area is a time-consuming process. Particularly, there is a need in such cases to study the geographical and climatological features of the area (e.g., tropical region, temperate region, etc.), including surveying relevant academic literature. Model configurations for other areas with similar characteristics are typically studied. The domain which covers the target area, constrained by available business applications, needs to be set up and, in that connection, domain resolution needs to be determined, often subject to severe practical constraints.
Even beyond the challenges just mentioned, initial model configuration parameters then need to be decided, e.g., physics, micro-physics, dynamics, and cumulus parameters (among a very large set of parameters in general). The weather model needs to be run on a computing platform for hindcasting several past events (which involves testing one or more forecasts retrospectively) that are representative of associated business applications, and configuration parameters need to be fine-tuned and updated for improved accuracy and for restricting the computational requirements to desired limits. Overall, significant manual intervention and domain expertise are normally required in a model setup phase, often far out of proportion to the quality and usefulness of the product derived.